"They kept saying 'one more hour; one more hour'." That was the lead to a story in my local paper about a flight that finally left Los Angeles after an extended delay and arrived at Medford, Ore., its final destination, a bit over 24 hours late. And it's the kind of story that has travelers and reporters asking:

"What are my rights in a really long delay?"

The short answer, as usual is, "Essentially none, beyond what the airline wants to give you."

A Tale of Woe

The flight that touched off this report was on Allegiant, scheduled to depart Los Angeles at 8:55 a.m. nonstop to Medford for arrival at 10:55 a.m. Passengers reported that the airline told them the flight would be delayed, first because the plane's windshield had to be replaced, then that a replacement plane would be flown in from Las Vegas, the airline's headquarters. Apparently, the replacement plane never arrived. Instead, mechanics repaired the original plane, which finally departed at 4:55 pm.

Sadly, the passengers' sighs of relief were premature, because after 45 minutes, the pilot announced some cabin pressure loss and that the plane would return to Los Angeles. Once back on the ground, and apparently after some badgering by passengers, Allegiant agreed to provide hotel rooms for the night. The flight finally left Los Angeles at about 10 a.m. and arrived at Medford 25 hours late. Before the ordeal was over, Allegiant offered the travelers one free round-trip ticket plus a future $50 credit.

Travelers waiting in Medford for the plane's turnaround flight out also faced that 25-hour delay. Allegiant apparently offered them the same package of discounts and freebies -- but no replacement plane.

No Government Rules

People almost always respond to a report such as this by asking what their rights might be in such a case. For some reason, many seem to think that some federal regulations or requirements govern problems of this sort, but they don't. For all practical purposes, the only actual federally mandated rights you have are (1) the well publicized right to compensation in the event of bumping off an oversold flight and (2) the new right to get off a plane stuck on the tarmac more than three hours (with a few exemptions). Beyond that, if you're caught in a long delay such as this, your only rights are whatever the airline's official "contract of carriage" provides.

Airline Contracts Govern

All U.S. airlines file official "contracts of carriage" and display them online. Those contracts contain the provisions that actually bind the airline to what it will do for you -- as well as what you must do for the airline. And those contracts include what an airline promises to do in the case of "irregular operations."

Allegiant's contract says: "In the event Carrier cancels or fails to operate any flight according to Carrier's published schedule, or changes the schedule of any flight, Carrier will, at the request of a passenger confirmed on such flight transport the passenger on another of Carrier's flights on which space is available at no additional charge; or refund the unused portion of the passenger's fare." That's par for the course.

In this case, Allegiant actually went beyond its contractual requirements: It covered overnight accommodations and provided tickets and credits, neither required by the contract.

What Allegiant did not do was transfer those travelers to flights on other airlines. Although no other airline's single flight could have accommodated a full planeload of Allegiant travelers, presumably some combination of flights on Horizon and United could have allowed travelers to get home some time the original evening rather than the following noon. Unfortunately, Allegiant's contract does not provide this option, and because Allegiant has no transfer agreements with other lines, it did not offer it.

Rule 240; Alive, but Fading

Before deregulation, the legacy airlines all filed tariffs with a "Rule 240" provision committing them to transfer passengers to another line in the event of such delays. Contrary to popular belief, however, that provision was always just a part of each line's tariff, not a government rule as most of us understand the term.

Some of the legacy lines still retain a few "Rule 240" elements in their contracts. The last time I checked, Alaska, Continental, JetBlue, United, and US Airways still promise to transfer you, but only to another line with which it has a transfer agreement. Delta says it can transfer you, but only at its "sole discretion;" American promises only to get you on one of its own flights.

Southwest and some other low-fare lines have no transfer agreements with other lines and thus promise only to transfer you to a later flight (or give you a refund). With frequent flights on most routes, Southwest's "later flight" promise may be a good bet. On Allegiant, the next flight may not be for three or four days. This is one reason, said a travel agent friend, that her agency does not sell Allegiant tickets, despite the great fares that line offers.

In my comments to the Department of Transportation regarding proposed new air travelers' rights, I recommend universal and mandatory "Rule 240" transfer in the event of cancellations or extended delays. I doubt, however, that will actually happen.

What to Do

The upshot of this case is clear: limited options in the case of delay is one of several risks you take when you fly a smaller, low-fare line. The risk is minimal; such delays are rare. But they do happen, and you have to decide if the great difference in fares justifies that risk.

Ed Perkins is a SmarterTravel contributing editor and a respected commentator on all aspects of the travel industry, including passenger comfort and rights, travel insurance, the best credit cards for travelers, and car rental. This article originally appeared on SmarterTravel